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Symptoms

After an infected mosquito bites a human, the first symptoms of Zika can develop in 3 to 12 days but it can be shorter or longer in some people.

The majority of people infected with Zika virus have no symptoms. For those with symptoms, Zika virus tends to cause a mild, short-lived (2 to 7 days) illness.

Signs and symptoms suggestive of Zika virus infection may include a combination of the following:

rash

itching or pruritus

fever

headache

arthralgia or arthritis

myalgia

conjunctivitis

lower back pain

retro-orbital pain

The symptoms of Zika are similar to dengue (caused by a related flavivirus) or chikungunya (an alphavirus), which are often co-circulating in areas where Zika virus is present. Laboratory testing is essential for the correct diagnosis.

Treatment

There is no specific antiviral treatment for Zika. Supportive nursing care and relief of symptoms are the standard treatment.

Complications

Serious complications and deaths from Zika are not common. However, based on a growing body of research there is scientific consensus that Zika virus is a cause of microcephaly and other congenital anomalies (also referred to as congenital Zika syndrome), and Guillain-Barré syndrome (World Health Organization (WHO), 14 April 2016).

There are case reports describing acute disseminated encephalomyelitis (ADEM) and encephalopathy in patients with confirmed Zika virus infection. To date, a small number of deaths have been reported in adults and children, predominantly in individuals with underlying health conditions.

The WHO International Health Regulations (IHR) Emergency Committee (EC) has met on 3 occasions regarding Zika virus. At the meeting on 14 June 2016, the Director-General declared that Zika virus infection and its associated congenital and other neurological disorders continues to constitute a Public Health Emergency of International Concern (PHEIC).